Nice, I quite like the art style and music. 

Some thoughts:

- It's strange having the jump button be 'w' and the attack be on space, it makes jumping challenging since you have to hold 'w' and a direction key to effectively jump.  

- I got stuck in a pit near the beginning of the game and couldn't find a way out

- Some of the collisions (?) for platforms seem finicky

Overall, it's a great start!